There are two checks against the agreed upon "right thing",the national executive who has to agree with the consensus, and (thanks John Marshall), a system of (

There are two checks against the agreed upon "right thing",the national executive who has to agree with the consensus, and (thanks John Marshall), a system of (theoretically) impartial courts which can decide if the "right thing" is actually allowed according to the rules of the game (Constitution). The slavery compromise was exactly that. First the 3/5th agreement, then the Missouri compromise, then finally, when one side got all of the power (which is what the system is supposed to mitigate the chances of) a shooting war. Lincoln likely wouldn't have gone quite so agro on slavery if not for succession. And there likely wouldn't have been a United States if there hadn't been any compromises on slavery. The two sides would have split at the outset, and either 1) neither would have been able to amass enough influence on the continent and they'd have been reabsorbed by a European power 2) after a hundred years of independent growth and simmering hatred, the two nation's would have had a war even more disastrous than the American civil war.